Sprake does not record any Alpha postcards, but does record the Stevens equivalent of the card above. He describes the first flag as being that of Holland, with Stevens having woven the colours in the wrong order.
Historically though, the initial allies in the First World War were Russia, Great Britain, France and Belgium. The first flag on the silk above is actually that of Russia, as used until the Soviet Union was established in 1917, and the colours are woven in the correct order.